The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Turbochargers are used for many applications. A turbocharger includes a pump portion and a turbine portion. Turbochargers are used for recovering energy from a pressurized stream of fluid. Excessive pressure in the turbine portion is used to drive the pump portion. One use for a turbocharger is recovering energy from a brine outlet of a reverse osmosis membrane assembly.
Reverse osmosis systems operate in a wide range of operating conditions for any given flow while seeking to maintain a high level of performance. Various turbine configurations are known for improving levels of performance for the turbine.
In one known turbine, single volute nozzle volute systems use a valve stem to allow bypass fluid from the turbine inlet to the impeller. Some improvement in performance is achieved. However, single nozzle volute bypass has lower efficiency and unbalanced radial load on the impeller due to the pressure distribution around a periphery.
Another type of turbine system is a variable vane nozzle that has moving vanes to change the vane nozzle size. One problem with this configuration is lower efficiency due to losses at the entrance to the vane, lower efficiency due to leakage through the moving part clearances, the mechanical parts are subject to wear and the complex assembly procedure involved in assembling the variable vane.